Ethyl p-methoxycinnamate Exhibits Superior Multi-Modal Anti-Inflammatory Activity Compared to Structurally Related...

This study aimed to investigate the anti-inflammatory potential of cinnamic acid (CA) and its derivatives, ethyl p-methoxycinnamate (EPMC) and trans-4-methoxy cinnamic acid (APMC), using integrated in silico, in vitro, and in vivo approaches to identify safer alternatives to conventional nonsteroidal anti-inflammatory drugs (NSAIDs).

Molecular docking was performed to evaluate binding interactions with inflammation-related proteins, including heat shock protein 90 alpha family class A member 1 (HSP90AA1), Janus kinase 2 (JAK2), prostaglandin-endoperoxide synthase 2 (PTGS2), lipoxygenase, heat shock protein 90 beta family class B member 1 (HSP90AB1), and nitric oxide synthase 3 (NOS3). In vitro anti-inflammatory activity was assessed using bovine serum albumin (BSA) denaturation assays to determine the half-maximal inhibitory concentration (IC50). In vivo efficacy was evaluated using a carrageenan-induced paw edema model in mice (n = 3 per group), and hematological analysis was conducted 3 hours post-induction.

Molecular docking revealed that EPMC exhibited superior multi-target binding affinities across five inflammatory proteins compared with allyl p-methoxycinnamate (APMC) and CA, with notable interaction with prostaglandin-endoperoxide synthase 2 (PTGS2/COX-2) interaction (-6.29 kcal/mol). CA uniquely bound NOS3 (-3.06 kcal/mol), suggesting distinct mechanistic pathways. BSA denaturation assays demonstrated comparable IC50 values for EPMC (170.02 μg/mL), CA (171.48 μg/mL), and diclofenac sodium (165.05 μg/mL), whereas APMC exhibited weaker activity (215.06 μg/mL). In vivo, EPMC produced the most rapid and complete resolution of inflammation, achieving significantly lower area-under-curve values than diclofenac sodium (p < 0.05). Hematological analysis revealed mechanistic divergence APMC (600 mg/kg) tended to normalize white blood cell (WBC) and lymphocyte counts, suggesting systemic immunomodulation, whereas EPMC and CA demonstrated localized anti-inflammatory action without hematological effects.

EPMC demonstrates superior multi-modal anti-inflammatory activity through multi-target engagement and localized tissue action, positioning it as a promising lead for next-generation anti-inflammatory therapeutics with potentially improved safety profiles compared with conventional NSAIDs.